Reportable Segments - NOI from Our Rental Real Estate for Each Segment Specific to Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Rental income	$ 705,088	$ 653,348
Operating income	297,588	149,738
Total Assets	20,102,526		$ 20,218,262
Same Store
Segment Reporting Information [Line Items]
Rental income	681,675	624,366
Operating expenses	226,790	211,535
Operating income	454,885	412,831
Total Assets	18,209,289
Capital Expenditures	48,137
Non-same store/other
Segment Reporting Information [Line Items]
Rental income	23,413	28,982
Operating expenses	17,458	14,027
Operating income	5,955	14,955
Total Assets	1,893,237
Capital Expenditures	7,255
Same Store, Non-same Store and Other
Segment Reporting Information [Line Items]
Rental income	705,088	653,348
Operating expenses	244,248	225,562
Operating income	460,840	427,786
Total Assets	20,102,526
Capital Expenditures	55,392
Los Angeles | Same Store
Segment Reporting Information [Line Items]
Rental income	115,681	108,969
Operating expenses	37,801	34,184
Operating income	77,880	74,785
Total Assets	2,536,079
Capital Expenditures	8,189
Orange County | Same Store
Segment Reporting Information [Line Items]
Rental income	31,588	28,767
Operating expenses	7,187	6,531
Operating income	24,401	22,236
Total Assets	352,643
Capital Expenditures	1,678
San Diego | Same Store
Segment Reporting Information [Line Items]
Rental income	22,441	20,940
Operating expenses	5,189	4,952
Operating income	17,252	15,988
Total Assets	229,293
Capital Expenditures	4,055
Subtotal - Southern California | Same Store
Segment Reporting Information [Line Items]
Rental income	169,710	158,676
Operating expenses	50,177	45,667
Operating income	119,533	113,009
Total Assets	3,118,015
Capital Expenditures	13,922
San Francisco | Same Store
Segment Reporting Information [Line Items]
Rental income	107,479	100,616
Operating expenses	34,005	31,673
Operating income	73,474	68,943
Total Assets	3,046,849
Capital Expenditures	7,954
Washington D.C. | Same Store
Segment Reporting Information [Line Items]
Rental income	107,623	100,705
Operating expenses	36,268	34,211
Operating income	71,355	66,494
Total Assets	3,064,106
Capital Expenditures	8,674
New York | Same Store
Segment Reporting Information [Line Items]
Rental income	118,045	99,830
Operating expenses	49,771	47,875
Operating income	68,274	51,955
Total Assets	3,377,729
Capital Expenditures	5,450
Seattle | Same Store
Segment Reporting Information [Line Items]
Rental income	74,561	68,537
Operating expenses	20,479	19,927
Operating income	54,082	48,610
Total Assets	2,157,123
Capital Expenditures	5,311
Boston | Same Store
Segment Reporting Information [Line Items]
Rental income	70,658	64,663
Operating expenses	22,636	21,059
Operating income	48,022	43,604
Total Assets	1,792,839
Capital Expenditures	5,145
Denver | Same Store
Segment Reporting Information [Line Items]
Rental income	17,597	16,232
Operating expenses	5,491	4,633
Operating income	12,106	11,599
Total Assets	848,783
Capital Expenditures	561
Other Expansion Markets | Same Store
Segment Reporting Information [Line Items]
Rental income	16,002	15,107
Operating expenses	7,963	6,490
Operating income	8,039	8,617
Total Assets	803,845
Capital Expenditures	1,120
Non-same store | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	20,970	15,050
Operating expenses	7,409	7,752
Operating income	13,561	7,298
Total Assets	1,007,584
Capital Expenditures	7,196
Other | Non-same store/other
Segment Reporting Information [Line Items]
Rental income	2,443	13,932
Operating expenses	10,049	6,275
Operating income	(7,606)	$ 7,657
Total Assets	885,653
Capital Expenditures	$ 59